The present invention relates to materials which are usefully applicable to engine component parts, such as pistons, connecting rods, intake valves, valve lifters, valve spring retainers, cylinder liners, and so on, of automobiles, aircraft, or the like. In particular, it relates to an aluminum alloy powder, an aluminum alloy and an aluminum alloy-based composite material (hereinafter simply referred to as an "Al alloy-based MMC") which are not only excellent in the strength at high temperatures but also in the sliding characteristic.